Surface-active urethanes and a process for preparing them



United States Patent M There have already been described surface-activecompounds carrying carboxyl or sulfonic acid groups which are obtainedby the reaction of aminoacetic or aminoethanesulfonic acids that areeither unsubstituted at the nitrogen or substituted with low molecularWeight alkyl radicals or the phenyl radical, with chlorocarbonic acidesters obtained from alcohols containing 9 or more carbon atoms. Therehave also already been described surface-active compounds which areprepared by the reaction of chloroformic acid esters obtained fromalcoholscontaining 6-8 carbon atoms and derived fromthe oxosynthesis andwhich, in addition, contain methyl groups Bfihhfidh Patented Apr. 23,1963 which are linked via the amino group with the low mo lecular weightalkyl radical X which contains about 1-3 carbon atoms and is substitutedat the terminal group by an acid group Y such as -COOH or -SO H, andform the mentioned compounds of the formula As such compounds, thereenter into consideration for 0 the process of the present inventionespecailly the aminoas side chains, with primary or secondaryaminocarboxylic acids, aminosulfonic acids or amino-sulfuric acidesters.

The wetting power of these known products is still insufficient for manypurposes.

Now we have found that surface-active compounds which display asubstantially greater wetting power and correspond to the generalformula wherein R represents an alkyl group which contains 8-12 carbonatoms and forms either a straight chain or is branched with l-4 sidechains, preferably l-3 side chains, containing each 2-6, especially 2-4,carbon atoms, R represents an alkyl group which contains 8 carbon atomsand constitutes either a straight chain or is branched preferably withone side chain containing 2-4, preferably 2, carbon atoms, X representsa low molecular weight alkylene radical containing about l-3 carbonatoms, and Y represents a carboxyl or a sulfonic acid group in the freeform or in the form of the water-soluble salts thereof, can be obtainedby subjecting compounds of the general formula R NH-XY wherein R X and Yhave the meanings given above, with chlorocarbonic acid esters of thegeneral formula wherein R has the meaning given above, to a reactioncorresponding to the Schotten-Baumann reaction (cf. L. Gattermann, DiePraxis des organischen Chemikers, 32nd edition, page 118 (1947)).

The compounds of the general formula constitute secondary amines, Rhaving the aforementioned meaning of an alkyl radical which contains 8carbon atoms and which may either form a straight chain or a branchedchain. As branched hydrocarbons enter into consideration preferablythose having a side chain containing 2-4 carbon atoms. As alkyl radicalsR of this type, there may be mentioned by Way of example:

acetic acid, the S-aminopropane-sulfonic acid-(l), and the2-aminopropane-sulfonic acid-(l) and particularly theZ-amiuo-ethane-sulfonic acid-(1), each of which carries the abovedefined radical R at the nitrogen atom. fi- Aminopropionic acid, whichis substituted with R is also suitable.

As chlorocarbonic acid esters of the general formula wherein Rrepresents an alkyl radical containing 8-12 carbon atoms and formingeither a straight chain or being branched with side chains eachcontaining 2-6, especially 2-4, carbon atoms, there are mentioned by wayof example, the following:

Particularly suitable are the compounds and such compounds as haveterminal branchings and chlorocarbonic acid ester groups at thesecondary hydroxyl groups, for example,

The last mentioned compound imparts to the surfaceactive agents preparedtherefrom a surprisingly high wetting power which is particularlyeffective even at elevated temperatures.

The surfaceactive compounds are prepared according to this inven-tion bysubjecting thecomponent preferably in the form of its salts and, ifnecessary, in solvents, for example, water or low molecular weightalcohols, e.g. methanol, ethanol, propanol, or mixtures of thesealcohols with one another or with water, to the reaction with thechlorocarbonic acid esters of the formula R-O-CO-Cl in the manner assuch known of the Schotten-Baumann reaction. For the salt formation withthe carboxylic acid groups or sulfonic acid groups, there enter intoconsideration particularly the alkali metal or alkaline earth metalions, or the ion of ammonia. Sodium, potassium or ammonium salts arepreferably used.

The solution of the amine component is reacted with the chlorocarbonicacid ester advantageously in the presence of a substance capable ofbinding the hydrochloric acid formed during the reaction. The solutionof the component R -NH-XY can be preliminarily mixed with an equivalentamount of acid-binding agenteither in solid form or in the form of asolutionand then the chlorocarbonic acid ester may be added slowly,

metic and pharmaeeutic preparations.

preferably while stirring. Particularly suitable is a process in whichthe acid-binding substance is added in an equivalent quantity or in anexcess quantity gradually at the rate of which the component R -NHXYreacts with the chlorocarbonic acid ester slowly added while regulatingthe rate of addition so as to ensure maintenance of a pH value of about6 to about 12, preferably 8-10, in the reaction mixture.

The reaction can be carried out at a temperature in the range of aboutC. and about 120 C., preferably about C. and about 80 C. In general, thereaction may be carried out without additional cooling or heating. It isoften advantageous to maintain the reaction temperature, at first bycooling, at between 0 C. and 30 C., and then to finish the reaction, ifnecessary under pressure, at an elevated temperature, for example, up to120 C. In some individual cases it is possible to carry out the reactionwithout the use of a.solvent.

As acid-binding agents, that are suitable to bind the hydrogen chlorideformed during the reaction, there enter into consideration, for example,inorganic hydroxides, carbonates or bicarbonates, especially of thealkali metals and alkaline earth metals and organic bases, preferablytertiary bases, for example, pyridine, N-ethylpiperidine,trimethylamine, triethylamine and triethanolamine.

There may also be used mixtures of various compounds of the generalformula R --NHXY and/ or mixtures of the chlorocarbonic acid estersconcerned. Thereby are often obtained products that have a particularlyfavorable solubility.

The urethanes' obtained by the process of the present invention possessan unequalled wetting power as compared with known products. Thisresults clearly from a Comparison of the wetting values of the compoundsgiven in Tables I and H. Furthermore, the products of the presentinvention possess an increased fastness to saponification so that theymay also be used in acid and alkaline liquors, even at elevatedtemperatures. Some of the novel products are distingiished by anexcellent wetting power in the heat.

The urethanes obtained by the process of the present invention may beused as rapid wetting agents in the textile industry, for example, fordyeing, printing, bleaching, mercerising, fulling, carbonisinkier-boiling, finishing, and in other industries where rapid wetting isdesired, for example, in the leather industry, in galvanizations, in theproduction of construction auxiliaries and of cos- In order to increasethe wetting speed, they may also be added to other surface-activesubstances or mixtures of substances, for example, emulsifiers,emulsions, detergents, swelling agents, unsoluble suspension auxiliariesor even mixtures of organic solvents.

The following examples serve to illustrate the invention'but they arenot intended to limit it thereto:

EXAMPLE 1 259 kg. of the sodium salt of Z-ethylhexyl-aminoethanesulfonicacid in form of an aqueous solution of strength are introduced into avessel with stirrer, holding 2 m. and provided with devices for heatingand cooling and a heatable bottom outlet. To this solution are added inthe course of about 2 hours at about 20 C. and while slowly stirring(about 60 r.-p.m.), 192.5 kg. of 2-ethyl-hexyl-chloro-carbonic acidester, and the mixture is constantly maintained alkaline with respect tophenolphthalein by adding about 1 mol (=41 kg.) of NaOH in the form of aconcentrated lye. The thickly pasty mixture is further stirred for 1hour at 45 C., then cooled to 20 C., and neutralized by adding in smallportions about 80 kg. of hydrochloric acid of about 10% strength. Thethickly pasty reaction mixture is then kneaded for 10 minutes at about20 C. with about 100 kg. of common salt until the reaction productseparates in the form of a jelly. The solution of salt is withdrawn bythe bottom outlet. The remaining jelly-like reaction product is fused at98 C. during the night and then drawn off" at this temperature.

Yield: 380 kilograms of product in the form of a paste of 45% strength.

Already in a concentration or" 0.15 gram of washingactive substance perlitre of neutral water having a temperature of 20 C., the compound has awet-ting time of 100 seconds, measured with a standardized circularcotton fabric put on the surface of the solution (funnel method).According to this method, a circular cotton fabric (diameter 3 cm.) of0.4 gram in weight is put on 1 litre of distilled water having atemperature of 20 C. and pressed by means of a glass funnel below thesurface of the liquid, and the amount of wetting agent is determinedwhich is necessary for causing the fabric to sink within 100 seconds(cf. K. Lindner, Textilhilfsmittel und Waschrohstoffe (1954), page 829).The wetting values of other urethanes prepared by the process of thepresent invention are given in the following Table I.

Instead of the sodium salts of the above-mentioned sulfonic acids, theremay also be used the corresponding potassium or calcium salts, in whichcase the corresponding hydroxides, such as potassium hydroxide orcalcium hydroxide, respectively, may then be used, if necessary, ashydrogen chloride binding substances.

EXAMPLE 2 209 kg. of the sodium salt of 2-ethylhexyl-amino-acetic acidin the form of an aqueous solution of 20% strength are introduced into avessel with stirrer, having a capacity of 2 m. and being'provided withdevices for cooling and heating and a heatable bottom outlet. To thissolution are added at about 20 C. in the course of 2 hours and whileslowly stirring (about 65 r.p.-m.), 192.5 kg. ofZ-ethylhexyl-chlorocarbonic acid ester, and the mixture is constantlymaintained alkaline with respect to phenolphthalein by adding about 1mol (=about 41 kg.) of NaOH in the form of a concentrated lye. Thethickly pasty mixture is further stirred for one hour at 45 C., thencooled to 20 C., and finally neutralized by adding in small portionsabout kg. of hydrochloric acid of about 10% strength. The thickly pastyreaction mixture is then kneaded for 10 minutes at about 20 C. withabout kg. of common salt until the reaction product separates in theform of a jelly. The solution of salt that has separated is withdrawn bythe bottom outlet. The remaining jelly-like reaction mixture is fusedover night at about 98 C. and then drawn off at this temperature.

Yield: 335 kg. of reaction product in the form of a paste of about 45%strength. I

The wetting values of known urethanes are given in the following TableII.

Already in a concentration of 0.20 gram of washingactive substance perliter of neutral water (pH 7) having a temperature of 20 C., thecompound shows a wetting time of 100 seconds, measured on standardizedcircular cotton fabric put on the solution (funnel method, cf. Ex-

ample 1).

Table II Alkyl-chloroformic acid Wetting Amino component ester value(g./1.)

(a) 2+:thy1hexyltaurine 3-methyl-hexyl-chloroiormic 0.27

acid ester.

(b) 2-ethylhexyltaurine oleylchloroformic acid ester.. 5

() 2-ethylhexyltaurine Z-ethylbutylchloroiormic 0.52

acid ester.

(11) N-butyl-taurine Z-ethylhexyl-chloroformic 1.28

acid ester.

(0) N-butyl-taurine dodrzcyl-chlorotormic acid 1.55

es er.

(1)1sobutyl-taurine 2-ethylhexy1-ehloroformic 1.02

acid ester.

(0) isobutyl-taurine dodtzcyl-chloroformic acid 0.6

es er.

(h) isobutyl-taurine trimethylnonyl-chiorofonnic 0.46

acid ester.

(i) isobutyl-taurine 2-butyIoctyl-chloroiormic 0.62

acid ester.

(j) isobutyl-taurinediisobutylcarbionol-chioro- 1.5

formic acid ester.

(k) cyclohexyi-taurine 2-ethylhexyl-chloroformic 1.15

acid ester.

(1) methyl-taurmeu 1.5

(m) methyl-taurine. oleyl-chloroformic acid ester 3. 75

('n) dodecyl-taurlne. 2ethylhexyl-chloroformic 0.96

acid ester.

(0) Z-ethylhexyl-glycocoll. Z-ethylbutyl-chloroformic 0.52

acid ester.

(1)) 2-ethyihexyl-glycocoll...... oleyl-chloroformie acid ester- Weclaim: 1. Surface-active compounds of the formula R0 mmomomsmm wherein Ris an alkyl radical having 812 carbon atoms and R is a member selectedfrom the group consisting of 2-ethyl-hexyl and n-octyl.

2. A surface-active compound as in claim 1 wherein R is n-octyl and R isn-octyl.

3. A surface-active compound as in claim 1 wherein R is Z-ethyl-hexyland R is Z-ethyI-hexyl.

4. A surface-active compound as in claim 1 wherein R isdi-isobutylcarbino and R is 2-ethy1-hexyl.

5. A surface-active compound as in claim 1 wherein R is n-octyl and R is2-ethyl-hexyl.

6. A surface-active compound as in claim 1 wherein R is dodecyl and R is2ethy1-hexyl.

References Cited in the file of this patent UNITED STATES PATENTS1,933,945 Uln'ch et al. Nov. 7, 1933 2,157,362 Ulrich et al. May 9, 19392,722,551 Snell et a1. Nov. 1, 1955 FOREIGN PATENTS 599,692 Germany July7, 1934 854,796 Germany Nov. 6, 1952 31,851 Netherlands Jan. 15, 1934112,827 Sweden Jan. 2, 1945

1. SURFACE-ACTIVE COMPOUNDS OF THE FORMULA